2019 ASHS Annual Conference

Over the last 80 years, genetic gains for increased fruit firmness, yield, shelf-life, and other attributes essential for year-round production and long-distance shipping have been significant in strawberry. While heirloom cultivars produce low yields of highly perishable, short shelf-life fruit, modern cultivars produce high yields of long shelf-life fruit that can withstand the rigors of harvest, storage, and long-distance shipping. Genome-wide analyses of nucleotide diversity have uncovered selective sweeps and population stratifications that are strongly correlated with populations developed for different end-markets, shelf-life requirements, and production environments. Genetic mechanisms underlying these phenotypic differences are poorly understood and understudied. Here, we report on genome-wide association and genomic prediction studies geared towards identifying loci and developing insights into the genetics of fruit quality traits that either determine or are pleiotropically affected by genetic variation for shelf-life. We developed a training population of 400 half-sib individuals developed from crosses between an extremely high yielding, extra firm, long shelf-life cultivar (UCD9) and four highly perishable short shelf-life cultivars, two from western European and two from the southeastern US. These populations were genotyped with a 49,000 SNP array anchored to the octoploid reference genome and are currently being phenotyped for several fruit quality traits. We will report our initial findings, including GWAS results and the accuracy of genomic predictions for sugars, acids, firmness, and other important determinants of fruit quality in short and long shelf-life germplasm.